Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 310022 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 822 PM EDT MON MAY 30 2016 .SYNOPSIS... The remnants of Bonnie will linger along the South Carolina coast tonight, before slowly working northeast to the North Carolina coast Tuesday. A cold front arriving from the west Thursday into Friday will finally boot Bonnie out to sea by the end of the week. && .NEAR TERM /THROUGH TUESDAY/... As of 640 pm EDT Monday... Convection across the western portion of the region is making slow but sure progress southeast into more central portions of the forecast area. Currently, the activity was clustered in to main regions, the Mountain Empire region of southwest Virginia, south into the mountains and foothills of northwest North Carolina. The region was across parts of Monroe County West Virginia, northeast into Bath County Virginia. Other than a few isolated, short lasting showers, eastern parts of the region have been precipitation free thanks to good subsidence on the northwest side of the remnants of Bonnie. Short term guidance still offers solutions of the ongoing precipitation to continue to gradually make its way southeast into eastern parts of the area as the evening and overnight progresses. Have made little change in the forecast other than highlighting in the very near term where precipitation chances will be highest. Also, have tweaked hourly temperatures and dew points based upon the latest observations and expected trends heading through the evening. As of 140 PM EDT Monday... Convection remains quite sparse across the region this afternoon despite moisture given lack of forcing under capping aloft to the northwest of the Bonnie remnant. However do expect more clusters to develop over the west as instability continues to increase along the faint front/shear axis, so keeping in low to mid chance pops into this evening mainly west of the Blue Ridge. Short term solutions then attempt to organize shra/tsra into a broken band upon heading out to the Blue Ridge near sunset, and into eastern sections prior to midnight before fading. This remains quite iffy given the wake subsidence region currently out east and timing after loss of heating. Thus plan to only include some low pops heading out into the Piedmont this evening with decreasing coverage mountains. Once any convection ends, expect enough clearing west to support areas of dense fog espcly valleys, with perhaps less out east given the more tropical atmosphere under some lingering clouds overnight. This may be enough to warrant an advisory across the mountains later so something to watch. Otherwise expecting another mild overnight given moist dewpoints with lows mainly 60 to 65 except for a few cooler 50s mountains. Faint boundary should shift east of the mountains Tuesday as the remnant tropical low remains stuck near ILM/MYR through the afternoon. Models again attempt to swing a band or two of deeper moisture into far eastern sections while keeping a low level convergence zone out west. This would again support more scattered nature deeper convection mountains as forecast CAPE values climb to above 1k J/KG despite only weak forcing aloft. However pwats remain quite moist so expecting more heavy rain potential as the continued low level north/ne trajectory under sw flow aloft will likely keep showers from moving too much. This more in line with the latest drier 12z ECMWF, so running again with mainly chance pops, although spots along and just east of the Blue Ridge may stay dry per lingering subsidence once fog/low clouds burn off. Kept highs closer to the warmer mos after a mild start with most in the 80-85 range. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 230 PM EDT Monday... Continued sluggish pattern will result in a repeat performance Tuesday night of that seen tonight with early convection likely giving way to fog and only isolated pops per latest drier Nam. Flow over the west should finally start to turn more southerly later Wednesday afternoon as the Bonnie remnant slides toward the Outer Banks by Wednesday night and a weak backdoor front slips toward the region from the north. Guidance also suggests that weak shortwave energy may eject across the mountains from the west later in the day with tropical moisture and instability still in place. This may allow for a bit more widespread scattering of convection Wednesday afternoon but still not overly impressed. Therefore bumped up pops a little but still moreso on the side of the drier Nam/Euro solutions at this point with still some weak subsidence in place. Again expect any evening convection to fade by midnight Wednesday night with added fog around overnight. Upper heights should start to decrease on Thursday with developing upper troffiness heading southeast toward the region preceded by a weak surface cold front in the afternoon. This will allow for a very congested scenario with the Bonnie remnant near HSE, weak subsidence over the Piedmont, and a pre-frontal convergence zone working into deep pwats over the west where aided by orographics and decent instability. However just how far east lift across the west gets remains uncertain given latest slower trends, but perhaps enough to include afternoon likely pops far western sections and higher chances out to the Blue Ridge. Temps again of the warm/humid flavor with lows mostly 60s and highs in the low/mid 80s. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 1245 PM EDT Monday... Gradual lowering of heights will continue into next weekend as the upper zonal flow starts to break down and eventually gives way to a more pronounced trough across the region into early next week. This should be preceded by passing surface cold fronts with the initial boundary approaching Thursday night and crossing the area Friday pending timing of a few differing model solutions. This looks to put the best coverage of convection over the mountains Thursday evening and then perhaps southern/eastern sections Friday. However appears decent chances to likely pops in order across the CWA per a typical slower scenario than guidance suggests given the lagging mean upper trough well to the northwest. Initial boundary should be to the south Saturday with a brief lull in showers possible before the true secondary front arrives Sunday. This boundary ahead of a rather potent chilly upper cold pool for early June that will pivot east across the region by Day7 and likely knock temps back to below normal levels for early next week. Ahead of the front looks like added bands of shra/tsra Sunday followed by more post frontal upslope nature western showers Monday. Otherwise warm and humid temps with highs at or above normal to prevail into Saturday despite some drying early in the weekend. This before seeing somewhat cooler and even drier air especially mountains by Monday as deeper cool advection arrives with highs mostly in the 70s west to around 80 east. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
As of 810 PM EDT Monday... Line of showers and thunderstorms was crossing southeast over the Blue Ridge at the start of the TAF forecast period. Thunderstorms will move close to or across the KBCB and KROA airports before 01Z/9PM. These showers and thunderstorms may impact KDAN and KLYH before 04Z/midnight but expect diminishing coverage and intensity. Dense fog is then likely across the valleys including KLWB/KBCB, with MVFR to IFR fog out east. Medium to low confidence as to how extensive IFR fog may be east of the Blue Ridge. Have kept mainly MVFR with potential at this point. Should see conditions improve to VFR shortly after sunrise on Tuesday. Repeat scenario then likely Tuesday afternoon with heating resulting in bands/clusters of convection over the mountains and lingering lighter showers with tropical moisture in the east. Models suggest the most KROA and KBCB are the most likely sites to have showers or thunderstorms in the afternoon. Lower confidence that tropical moisture in the east will spread as far inland as KDAN and KLYH. With the abundant moisture still in place on Tuesday the storms will still produce heavy rain with MVFR visibilities. EXTENDED DISCUSSION... Similar setup again Tuesday night with more fog around after any evening convection ends. Appears convection may be more isolated Wednesday as the area slides in between the next upstream cold front and the remnants of Bonnie near the coast. Thus more potential to see more widespread VFR Wednesday with exceptions over the east and with any pop up storms across the mountains. Finally an stronger upper trough will kick what is left of Bonnie out to sea Thursday-Friday. Expect more widespread showers Thursday afternoon into Friday ahead of a cold front, making for periods of sub-VFR ceilings and visibilities. Saturday may be VFR behind this front and before moisture and lowering conditions return by Saturday night.
-- End Changed Discussion --
&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH/WP NEAR TERM...DS/JH SHORT TERM...JH LONG TERM...JH AVIATION...AMS/JH is the U.S. government's official web portal to all federal, state and local government web resources and services.